在Python中手动更新Kivy RecycleView

Question

RecycleView isn't updating its table when data is changed from outside the RecycleView class. As a summary I'm trying to create a simple stock portfolio manager.

I have a custom RecycleView class which I call RecycleViewPortfolio that inherits from RecycleView. From my .kv file I have three buttons connected to functions populate_1, populate_2 and populate_3 within my RecycleViewPortfolio class. Whenever I press a button and call any of the populate functions, the RecycleView behaves as expected.

However whenever I change the RecycleView data from outside the RecycleViewPortfolio class the table doesn't update. For example I have setup a global variable which I have imported to both my .py file and .kv file. I would like to be able to update the table whenever this data in this global variable is changed.

I have tried looking at the documentation from Kivy which mentions different functions that are suppose to solve this issue. But I guess Im clueless to how to apply these methods.

import StackOverflow.globalvariables as GlobalVariables
from kivy.app import App
from kivy.uix.popup import Popup
from kivy.uix.button import Button
from kivy.uix.gridlayout import GridLayout
from kivy.uix.behaviors import FocusBehavior
from kivy.uix.recycleview import RecycleView
from kivy.uix.recyclegridlayout import RecycleGridLayout
from kivy.uix.recycleview.views import RecycleDataViewBehavior
from kivy.uix.recycleview.layout import LayoutSelectionBehavior
from kivy.properties import BooleanProperty, ListProperty, ObjectProperty


class AddPopup(Popup):
    """Popup for adding asset"""
    asset_name = ObjectProperty
    asset_price = ObjectProperty
    asset_amount = ObjectProperty
    currency = ObjectProperty
    asset_class = ObjectProperty
    wrapped_button = ObjectProperty()

    def __init__(self, *args, **kwargs):
        super(AddPopup, self).__init__(*args, **kwargs)

    def open(self, correct=True):
        super(AddPopup, self).open(correct)

    def save_asset(self):
        # Make sure no input is empty
        if self.asset_name.text.strip() and self.asset_price.text.strip()\
                and self.asset_amount.text.strip() and self.currency.text.strip()\
                and self.asset_class.text.strip():

            GlobalVariables.rv_data_global = [{'text': self.asset_name.text.strip()},
                                              {'text': self.asset_amount.text.strip()},
                                              {'text': self.asset_price.text.strip()}]
            self.dismiss()

class RecycleViewPortfolio(RecycleView):

    def __init__(self, **kwargs):
        super(RecycleViewPortfolio, self).__init__(**kwargs)
        self.populate_2()

    def populate_1(self):
        root = App.get_running_app().root
        root.add_popup.open(True)
        self.data = GlobalVariables.rv_data_global

    def populate_2(self):
        self.data = [{'text': str(x)} for x in range(0, 6)]

    def populate_3(self):
        self.data = [{'text': str(x)} for x in range(6, 12)]

class PortfolioRoot(GridLayout):
    """root to all screens"""
    add_popup = ObjectProperty(None)
    list = ListProperty([])

    def __init__(self, **kwargs):
        super(PortfolioRoot, self).__init__(**kwargs)
        self.add_popup = AddPopup()

    def test_set_data(self):
        GlobalVariables.rv_data_global = [{'text': str(x)} for x in range(12, 18)]



class SelectableRecycleGridLayout(FocusBehavior, LayoutSelectionBehavior, # View Behavior
                                  RecycleGridLayout):
    ''' Adds selection and focus behaviour to the view. '''


class SelectableButton(RecycleDataViewBehavior, Button): # Data Behavior
    ''' Add selection support to the Label '''
    index = None
    selected = BooleanProperty(True)
    selectable = BooleanProperty(True)

    def refresh_view_attrs(self, rv, index, data):
        ''' Catch and handle the view changes '''
        self.index = index
        return super(SelectableButton, self).refresh_view_attrs(
            rv, index, data)

    def on_touch_down(self, touch):
        ''' Add selection on touch down '''
        if super(SelectableButton, self).on_touch_down(touch):
            return True
        if self.collide_point(*touch.pos) and self.selectable:
            return self.parent.select_with_touch(self.index, touch)

    def apply_selection(self, rv, index, is_selected):
        ''' Respond to the selection of items in the view. '''
        self.selected = is_selected


class PortfolioApp(App):
    """App object"""

    def __init__(self, **kwargs):
        super(PortfolioApp, self).__init__(**kwargs)

    def build(self):
        return PortfolioRoot()

PortfolioApp().run()

.kv file

    #:kivy 1.10.0
#:import GlobalVariables StackOverflow.globalvariables

<SelectableButton>:
    # Draw a background to indicate selection
    canvas.before:
        Color:
            rgba: (0, 0.517, 0.705, 1) if self.selected else (0, 0.517, 0.705, 1)
        Rectangle:
            pos: self.pos
            size: self.size
    background_color: [1, 0, 0, 1]  if self.selected else [1, 1, 1, 1]  # dark red else dark grey
    on_release:
        print("Pressed")

<WrappedLabel@Label>:
    size_hint_y: None
    height: self.texture_size[1] + (self.texture_size[1]/2)
    markup: True

<RecycleViewPortfolio@RecycleView>:
    viewclass: 'SelectableButton'
    target_id: None
#    id: rv_data_list
    data: GlobalVariables.rv_data_global
    SelectableRecycleGridLayout:
        cols: 3
        key_selection: 'selectable'
        default_size: None, dp(26)
        default_size_hint: 1, None
        size_hint_y: None
        height: self.minimum_height
        multiselect: True
        touch_multiselect: True

<PortfolioRoot>:
    BoxLayout:
        list: rv_data_list
        size: root.size
        orientation: 'vertical'
        WrappedLabel:
            text: "[b] Portfolio Manager [/b]"
            font_size: min(root.height, root.width) / 10
        GridLayout:
            size_hint_y: None
            height: root.height * 0.1
            cols: 4
            rows: 1
            #  Settings
            padding: root.width * 0.001, root.height * 0.001
            spacing: min(root.width, root.height) * 0.001

            Button:
                text: "Add"
                background_color: [1, 1, 1, 1]
                on_release:
                    rv_data_list.populate_1()
                    print("Add")

            Button:
                text: "Change"
                background_color: [1, 1, 1, 1]
                on_release:
                    rv_data_list.populate_2()
                    print("Change")

            Button:
                text: "Remove"
                background_color: [1, 1, 1, 1]
                on_release:
                    rv_data_list.populate_3()
                    print("Remove")

            Button:
                text: "Test"
                background_color: [1, 1, 1, 1]
                on_release:
                    root.test_set_data()
                    print("Test set data")

        RecycleViewPortfolio:
            id: rv_data_list

<AddPopup>:
    size_hint: 0.8, 0.8
    title: "Add Asset"
    title_size: root.height * 0.05
    auto_dismiss: False
    asset_name: asset_name
    asset_price: asset_price
    asset_amount: asset_amount
    currency: currency
    asset_class:asset_class
    wrapped_button: wrapped_button
    BoxLayout:
        orientation: 'vertical'
        GridLayout:
            rows: 5
            cols: 2
            padding: root.width * 0.02, root.height * 0.02
            spacing: min(root.width, root.height) * 0.02

            Label:
                id: asset_name_label
                text: "Asset name"
                halign: "center"
                font_size: root.height/25
                text_size: self.width, None
                center_y: .5
            TextInput:
                id: asset_name
                text: "Asset name"
                halign: "center"
                font_size: root.height/25
                text_size: self.width, None
                center_y: .5
            Label:
                id: asset_price_label
                text: "Asset price"
                halign: "center"
                font_size: root.height/25
                text_size: self.width, None
                center_y: .5
            TextInput:
                id: asset_price
                text: "asset"
                halign: "center"
                font_size: root.height/25
                text_size: self.width, None
                center_y: .5
            Label:
                id: asset_amount_label
                text: "Asset amount"
                halign: "center"
                font_size: root.height/25
                text_size: self.width, None
                center_y: .5
            TextInput:
                id: asset_amount
                text: "Asset amount"
                halign: "center"
                font_size: root.height/25
                text_size: self.width, None
                center_y: .5
            Label:
                id: currency_label
                text: "Asset currency"
                halign: "center"
                font_size: root.height/25
                text_size: self.width, None
                center_y: .5
            TextInput:
                id: currency
                text: "currency"
                halign: "center"
                font_size: root.height/25
                text_size: self.width, None
                center_y: .5
            Label:
                id: asset_class_label
                text: "Asset class"
                halign: "center"
                font_size: root.height/25
                text_size: self.width, None
                center_y: .5
            TextInput:
                id: asset_class
                text: "Asset class"
                halign: "center"
                font_size: root.height/25
                text_size: self.width, None
                center_y: .5
        Button:
            id: wrapped_button
            text: "Save"
            size_hint: 1, None
            height: root.height / 8
            on_release: root.save_asset()
        Button:
            id: wrapped_button
            text: "close"
            size_hint: 1, None
            height: root.height / 8
            on_release: root.dismiss()

globalvariables.py

# global variables
rv_data_global = []

I expect to be able to create a popup window where I add information which is stored in a global variable and after changes are made I call for the RecycleView to be updated.

Edit: Added a working example

This example shows how Im able to use the buttons "Change" and "Remove" in order to populate the RecycleView as expected. However when the add button is pressed and the popup window appears and the save button is pressed the RecycleView doesn't update. If the add button is pressed again and directly closed the RecyleView gets updated and shows the correct information.

The same goes for the "Test" buttons where I call a function which changes the global variable. From there I have no idea of how to update the view since Im no longer working underneath the RecycleView class.

TLDR; Method for manually updating the RecycleView after data has been changed.

Answer 1

I found the answers to one of my questions. By adding:

self.ids.rv_data_list.data = GlobalVariables.rv_data_global
self.ids.rv_data_list.refresh_from_data()

to the test_set_data function, I am now able to refresh the data as I requested. Hence the magic was the refresh_from_data() method.

Through the App.get_running_app() I was able to access the refresh_from_data() command from the popup class.

root = App.get_running_app().root
root.ids.rv_data_list.data = GlobalVariables.rv_data_global
root.ids.rv_data_list.refresh_from_data()

I seem to have solved my own issues here. But if anyone has a better or cleaner solution, please let me know.